I have an 08 with sport and optional 18" and I know there is no diff in suspension but I measured my wheel gaps so we could have some reference. From bottom edge of outside wheel well to top of tire is 1 7/8" F and 1 1/2" R. When I bought the car I was told the difference in ride height between xi and i with sport suspension was between 1/2 and 3/4 inch. I have driven both cars on the track and to call the xi wobbly is patently absurd. The car is more different to drive from the xdrive and the possible all seasons it has than from the suspension differences. I'm not saying the i sport suspension is not better I am merely saying lets keeps things in perspective. Sure it does not have that slammed look that for some reason many people on this board like but it is still a BMW. I have 17k miles on the car so it is settled and newer cars may vary.
2008 335xi | E90 | Spark Graph | Lemon | Poplar | ZPP | ZSP | Navi | CWP | 18" | HD Radio | CA | 6FL